Ring-shaped light-conducting apparatus with uniform luminance

Abstract

A light-conducting apparatus includes a light source, a light-conducting member and a light-reflecting structure. The light-conducting member includes a ring-shaped portion, a light-receiving surface and a radially outwardly bulged portion. The ring-shaped portion extends continuously over an entire circumference of the ring-shaped portion in a circumferential direction of the ring-shaped portion. The light-receiving surface causes light from the light source to enter the light-conducting member through the light-receiving surface. The radially outwardly bulged portion is bulged radially outwardly from the ring-shaped portion and causes the light having entered the light-conducting member through the light-receiving surface to enter the ring-shaped portion in one direction in the circumferential direction of the ring-shaped portion. The light-reflecting structure reflects a portion of the light having entered the light-conducting member through the light-receiving surface and causes the reflected light to enter the ring-shaped portion in a direction opposite to the one direction in the circumferential direction of the ring-shaped portion.

The invention claimed is: 
     
       1. A light-conducting apparatus comprising:
 a light source, 
 a light-conducting member, and 
 a light-reflecting structure, 
 wherein the light-conducting member includes a ring-shaped portion, a light-receiving surface and a radially outwardly bulged portion, 
 wherein the ring-shaped portion extends continuously over an entire circumference of the ring-shaped portion in a circumferential direction of the ring-shaped portion, 
 wherein the light-receiving surface causes light from the light source to enter the light-conducting member through the light-receiving surface, 
 wherein the radially outwardly bulged portion protrudes in a radial direction beyond the circumference of the ring-shaped portion outwardly from the ring-shaped portion such that the light-receiving surface is provided in a radial direction beyond the circumference of the ring-shaped portion outwardly away from the ring-shaped portion and the light having entered the light-conducting member through the light-receiving surface enters the ring-shaped portion in one direction in the circumferential direction of the ring-shaped portion, and 
 wherein the light-reflecting structure reflects a portion of the light having entered the light-conducting member through the light-receiving surface and causes the reflected light to enter the ring-shaped portion in a direction opposite to the one direction in the circumferential direction of the ring-shaped portion. 
 
     
     
       2. A light-conducting apparatus according to  claim 1 ,
 wherein the light-reflecting structure includes a layer provided at the radially outwardly bulged portion and a boundary surface located between the light-conducting member and the layer, a refractive index of the layer being different from a refractive index of the light-conducting member, and 
 wherein the portion of the light having entered the light-conducting member through the light-receiving surface is reflected at the boundary surface. 
 
     
     
       3. A light-conducting apparatus according to  claim 2 , wherein a medium of the layer is air. 
     
     
       4. A light-conducting apparatus according to  claim 3 , wherein the layer is a notch concave from a surface of the radially outwardly bulged portion. 
     
     
       5. A light-conducting apparatus according to  claim 2 , wherein an entirety of the light having entered the light-conducting member through the light-receiving surface and traveling to the boundary surface is reflected at the boundary surface. 
     
     
       6. A light-conducting apparatus according to  claim 2 , wherein a portion of the light having entered the light-conducting member through the light-receiving surface and traveling to the boundary surface is reflected at the boundary surface and a remainder of the light is refracted at the boundary surface to enter the layer. 
     
     
       7. A light-conducting apparatus according to  claim 1 , wherein the radially outwardly bulged portion protrudes radially outwardly from the ring-shaped portion such that the light having entered the light-conducting member through the light-receiving surface enters the ring-shaped portion in the one, tangential direction in the circumferential direction of the ring-shaped portion, and
 wherein the light-reflecting structure reflects the one portion, not an entirety of the light having entered the light-conducting member through the light-receiving surface and causes the reflected light to enter the ring-shaped portion in the direction tangential and opposite to the one, tangential direction in the circumferential direction of the ring-shaped portion.